I’ve been saying for a while that there’s nothing inherently expensive about 3D printing technology…at least not the FFF type. Assuming the technology becomes more popular over the next few years (which I do) I don’t see any reason why 3D printers couldn’t become as cheap and ubiquitous as 2D printers.

However, 3D printing has weaknesses, not the least of which is that it can’t work in metal.* You can take the plastic parts and cast metal parts from them, but the heat and gases have side effects that nobody in their right mind would ever allow inside a house. It is possible to work metal by machining it in a small CNC mill, as demonstrated by the ease of finding a desktop mill on Google. Since 3D printers and CNC mills function so similarly, why not combine both functions into one machine?

QU-BD is working on that. Openalia interviewed them back when they were coming off of a successful effort to Kickstarter their own thermoplastic extruder. Now they’ve arrived at the main event, the beta Rapid Prototyping Mill (RPM) pre-order. This design is important because it has the potential to create all of the (non-electrical) parts for a 3D printer, including its own extruder. Read through the interview with Chelsea Thompson after the jump to learn a little bit about the RPM and the Revolution, which is an all-metal frame 3D printer.

* I’m limiting the analysis to current technology. Sure, there might be an unforeseen breakthrough in materials science in the near future, but that’s a different discussion.